Skip to Main Content
Skip Nav Destination
GEOREF RECORD

Geochemistry of basement rocks and impact breccias from the central uplift of the Bosumtwi Crater, Ghana; comparison of proximal and distal impactites

Ludovic Ferriere, Christian Koeberl, Franz Brandstaetter and Dieter Mader
Geochemistry of basement rocks and impact breccias from the central uplift of the Bosumtwi Crater, Ghana; comparison of proximal and distal impactites (in Large meteorite impacts and planetary evolution IV, Roger L. Gibson (editor) and Wolf Uwe Reimold (editor))
Special Paper - Geological Society of America (September 2010) 465: 443-469

Abstract

Crater-fill impact breccia and basement rock samples from the 1.07 Ma Bosumtwi impact structure (Ghana) were recovered for the first time in 2004 during an International Continental Scientific Drilling Program (ICDP)-sponsored drilling project. Here, we present detailed results of major- and trace-element analyses of 119 samples from drill core LB-08A, together with the chemical compositions of melt particles from suevite. The meta-graywacke and phyllite/slate crater basement rocks can be easily distinguished from each other on the basis of their bulk chemical compositions. A comparison of the chemical compositions of crater-fill and fallout suevites, as well as between proximal and distal impactites, reveals that LB-08A suevites have higher MgO, CaO, and Na (sub 2) O contents than fallout suevites and, similarly, that the CaO and Na (sub 2) O contents are higher by a factor of approximately two in LB-08A suevites than in Ivory Coast tektites. Noticeable differences occur in Cr, Co, and Ni contents between the different impactites; higher abundances are observed for these elements in distal impactites. The observed differences in composition in the various impactites mainly reflect mixing of different proportions of the original target lithologies, as can be seen in the differences in the clast populations between crater-fill and fallout suevites. However, the original impactite compositions may have also been modified by postimpact alteration, particularly in the proximal impactites. Melt particles in suevite show significant differences in major-element compositions between the different samples investigated, but also within a given sample, indicating that they represent melts derived from different lithologies.


ISSN: 0072-1077
EISSN: 2331-219X
Coden: GSAPAZ
Serial Title: Special Paper - Geological Society of America
Serial Volume: 465
Title: Geochemistry of basement rocks and impact breccias from the central uplift of the Bosumtwi Crater, Ghana; comparison of proximal and distal impactites
Title: Large meteorite impacts and planetary evolution IV
Author(s): Ferriere, LudovicKoeberl, ChristianBrandstaetter, FranzMader, Dieter
Author(s): Gibson, Roger L.editor
Author(s): Reimold, Wolf Uweeditor
Affiliation: University of Vienna, Department of Lithospheric Research, Vienna, Austria
Affiliation: University of the Witwatersrand, School of Geosciences, Johannesburg, South Africa
Pages: 443-469
Published: 201009
Text Language: English
Publisher: Geological Society of America (GSA), Boulder, CO, United States
References: 51
Accession Number: 2011-013835
Categories: Geochemistry of rocks, soils, and sediments
Document Type: Serial
Bibliographic Level: Analytic
Annotation: Includes appendices
Illustration Description: illus. incl. 2 tables, sketch map
N06°30'00" - N06°30'00", W01°25'00" - W01°25'00"
Secondary Affiliation: Leibniz Institute at Humbaldt University Berlin, DEU, GermanyNatural History Museum, AUT, Austria
Country of Publication: United States
Secondary Affiliation: GeoRef, Copyright 2017, American Geosciences Institute. Reference includes data supplied by the Geological Society of America, Boulder, CO, United States
Update Code: 201109
Close Modal

or Create an Account

Close Modal
Close Modal